textproduct: Rapid City

KEY MESSAGES

- Severe storms possible across south-central South Dakota on Wednesday.

- Chance of severe weather with all hazards possible Thursday.

UPDATE

Issued at 1024 PM MDT Tue Jun 2 2026

Main focus this update is near-term pops and thunderstorm potential over the next couple days. Models have not handled location and overall progression of storm trends this evening. Low level jet strengthening tonight will allow storms to linger into the overnight hours, albeit losing a bit of their strength. Still could see some marginally severe pulse storms overnight. By morning storms should be more in central SD. As another disturbance pushes through the Dakotas Wednesday, some storms are expected to form along the boundary in the late afternoon early evening timeframe. Main concern will be over south central SD as the storms form. CAPE values in the 2000-3000 j/Kg and 30-40kt 0-6km shear will support some severe potential over south central SD. A better chance for more widespread storms with severe potential returns Thursday.

DISCUSSION

(This Afternoon Through Monday) Issued at 1109 AM MDT Tue Jun 2 2026

Upper level analysis has the forecast area in southwest flow with a low over southwestern Saskatchewan and a skinny ridge extending up through the Mississippi River Valley from High Pressure in the Southern Plains. At the surface, a cold front extends through eastern Montana into southeastern Wyoming. Radar imagery has thunderstorms already firing in the warm sector east of the boundary.

For this afternoon and evening, the cold front will provide the primary focus for thunderstorm development. As this front moves slowly east, development will likely occur over the Black Hills and most of western South Dakota, especially across northwestern South Dakota. Model soundings show steep lapse rates, deep layer sheer and MLCAPE around 2500 J/kg. These ingredients suggest the potential for supercell storms capable of producing large hail, severe winds, and even a tornadic storm. Additionally, the presence of a low level jet this evening should result in storms continuing through late evening and possibility into the early morning hours.

The cold front will move slowly east on Wednesday as the upper low slowly shifts into southeastern Saskatchewan and western Manitoba. Models indicate a secondary surface low will spin up over central South Dakota with a trailing cold front into western Nebraska panhandle. This boundary will once again be the focus for convective initiation during the afternoon and evening hours. Again, these storms will have the potential for large hail and strong wind gusts. Forecast soundings indicate steep lapse rates, MLCAPE around 2500 J/kg over central South Dakota, and shear up to 35-40kts over south central South Dakota, though shear is forecast to be much higher across north central South Dakota.

Thursday will be another big day for severe storms across the forecast area as the upper low slides through Manitoba and a shortwave crosses the Rockies into the forecast area by Friday afternoon and evening. At the surface, a low will spin up over southeastern Montana and slide into west-central Nebraska. This boundary will be the focus for severe storms on Thursday with diurnally enhanced development. The environment looks like a typical northern Black Hills supercell environment capable of very large hail. Additionally, storms may end up growing into an easterly propagating MCS overnight, resulting in a severe wind threat for south-central South Dakota by late evening.

On Friday, could have some lingering showers in the morning, as the cold front drops southward and a wave clips northwestern South Dakota. Also, some diurnally driven showers are possible over the Black Hills in the afternoon.

Saturday appears to be mainly dry as a weak shortwave ridge slides through the area, with chances for storms returning Sunday through early next week.

Temperatures through the period will gradually warm through this weekend, with highs running about 10 degrees above average and lows about 5 degrees above average.

AVIATION

(For the 12Z TAFS Through 12Z Thursday Morning) Issued At 522 AM MDT Wed Jun 3 2026

MVFR/IFR CIGs are ongoing over parts of northeastern Wyoming, the Black Hills, and northwestern SD this morning and will improve to VFR late morning. VFR conditions are then expected for both TAF sites the remainder of the day. More strong to severe storm development will be possible across south central SD late this afternoon.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.